ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Explore membership for yourself or for your organization.
Conference Spotlight
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
Latest Magazine Issues
Sep 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
September 2025
Nuclear Technology
Fusion Science and Technology
October 2025
Latest News
Empowering the next generation: ANS’s newest book focuses on careers in nuclear energy
A new career guide for the nuclear energy industry is now available: The Nuclear Empowered Workforce by Earnestine Johnson. Drawing on more than 30 years of experience across 16 nuclear facilities, Johnson offers a practical, insightful look into some of the many career paths available in commercial nuclear power. To mark the release, Johnson sat down with Nuclear News for a wide-ranging conversation about her career, her motivation for writing the book, and her advice for the next generation of nuclear professionals.
When Johnson began her career at engineering services company Stone & Webster, she entered a field still reeling from the effects of the Three Mile Island incident in 1979, nearly 15 years earlier. Her hiring cohort was the first group of new engineering graduates the company had brought on since TMI, a reflection of the industry-wide pause in nuclear construction. Her first long-term assignment—at the Millstone site in Waterford, Conn., helping resolve design issues stemming from TMI—marked the beginning of a long and varied career that spanned positions across the country.
Mitsuo Manaka
Nuclear Technology | Volume 143 | Number 3 | September 2003 | Pages 335-346
Technical Paper | Radioactive Waste Management and Disposal | doi.org/10.13182/NT03-A3421
Articles are hosted by Taylor and Francis Online.
Immediately after the geological disposal of high-level radioactive waste, the oxygen initially existing in the repository is expected to strongly affect the redox condition of the near field. The oxygen dissolves in the groundwater, is transported by diffusion through it, and is consumed by the oxidation of pyrite as an impurity in bentonite. To assess the influence of the oxygen, this study was conducted to estimate the diffusion of dissolved oxygen (DO) and the rate of pyrite oxidation by DO in compacted purified and crude sodium bentonites (SBs) in more detail than the Manaka et al. study. The effective diffusion coefficient (De) of DO in the compacted purified SB was measured in low ionic strength solution (carbonate buffered solution with pH ~ 9) using the electrochemical method. The empirical equation between De value of DO and dry density (0.5 × 103-1.8 × 103 kg m-3) of purified SB was obtained as follows:DeDOKunipia-F = 8.2 ± 1.5 × 10-10× exp(-2.6 ± 0.2 ×10-3,where DeDOKunipia-F is the De of DO in compacted purified SB (Kunipia F) (m2 s-1) and is the dry density of the SB (kg m-3).On the other hand, the De value of DO in the compacted crude SB was estimated using the relationship between De values of tritiated water in compacted purified and crude SBs. The empirical equation between the De value of DO and dry density (0.5 × 103-1.8 × 103 kg m-3) of crude SB was derived as follows:DeDOKunigel-V1 = 2.04 × 10-9 exp(-2.6 × 10-3),where DeDOKunigel-V1 is the De of DO in compacted crude SB (Kunigel V1) (m2 s-1) and is the dry density of the SB (kg m-3).The rates of pyrite oxidation by DO were estimated from the experimental data in pyrite-purified SB systems using the obtained De values of DO. The relation between rate constant (k') of pyrite oxidation by DO and dry density () of the SB was derived as follows:k' = 3.9 ± 1.1 × 10-8 exp(-1.3 ± 0.3 × 10-3),where k' is the rate constant at pH ~ 9 in compacted purified SB of dry density ranging from 0.8 × 103 to 1.2 × 103 kg m-3.The rate constants of pyrite oxidation by DO in the compacted crude SB (0.8 × 103 to 1.2 × 103 kg m-3) were also calculated using the estimated De values of DO. In general, the values of rate constants in the crude SB are 1.5 times as large as that in the purified SB.
